Any ideas what this little mark is by the rear wheel?

Lens Flare?

Would a hood minimize this?

 

Most probably lens flare, and no a hood would not make a difference in this particular example.

Your exif show a long shutter speed and almost wide open F3.5 its probably an artifact of the flourescent light being reflected just right from the wheel to the axis of your lens .

What lens did you use on your nikon exif suggest 18mm is where it was shot which is equiv to 27mm ff

 

do you have a filter on your lens?

 

It could be the filter making a reflection if you don't have a multi-coated filter, or it could even be caused by a smudge on your lens. I've seen just small areas of smudge cause something like that in the final result.

 

Zippy - I used the 18-55mm VR, and yea, 3.5 is wide open. Would that spot be a function of a wide aperture?

Nope, no filter.

I took many photos during that series, and none really had that mark....and I dont see anything too weird that I'd think a smudge would cause?

 

Actually if you look at things that are illumininated by any light source you will see reflections.

In this case i think its a simple case of you got a small reflection off the shiny wheel and your shutter speed being rather slow due to the low amt of light was open a bit longer resulting in that reflection being magnified and thats what you are seeing in your photo.

Now it looks like a simple combination of your lens and that reflection being in the right spot for that shot.

I doubt you could duplicate it and this is evidenced by your comment that this shot is the only one you see the "flare" in.

Light does reflect and if you have a trained eye a lot of times you can spot it in the viewfinder while composing the shot.

Some lenses are more prone to flare and I apologize but I am not a nikonian so I do not know the characteristics of the lens you used.

Maybe someone else will chime in on that particular lens characteristics.

 

Looks like flare to me.